Spin dependent inelastic collisions between metastable state two-electron atoms and ground state alkali-atoms

Experimentally the spin dependence of inelastic collisions between ytterbium (Yb) in the metastable 3P0 state and lithium (Li) in the Li ground state manifold is investigated at low magnetic fields. Using selective excitation all magnetic sublevels mJ of 174Yb(3P0) are accessed and four of the six lowest lying magnetic sublevels of 6Li are prepared by optical pumping. On the one hand, mJ-independence of collisions involving Li(F=1/2) atoms is found. A systematic mJ-dependence in collisions with Li(F=3/2) atoms, in particular suppressed losses for stretched collisional states, is observed on the other hand. Further, mJ-changing processes are found to be of minor relevance. The span of observed inelastic collision rates is between 1*10^{-11} cm^3/s and 40*10^{-11} cm^3/s, and a possible origin of the observed behavior is discussed.Comment: 12 pages, 4 figure

Spectroscopic determination of magnetic-field-dependent interactions in an ultracold Yb(3P2)-Li mixture

We present experimental results on the inelastic and elastic interspecies interactions between ytterbium (Yb) in the metastable ${}^3\mathrm{P}_2$ state loaded into a deep optical lattice and spin polarized lithium (Li) in its ground state. Focusing on the $m_J = 0$ magnetic sublevel of Yb(${}^3\mathrm{P}_2$), bias magnetic fields between 20 G and 800 G are investigated and significantly enhanced inelastic collision rates with high magnetic fields are found. In addition, by direct spectroscopy of the Yb Mott-insulator immersed in the Li Fermi gas an upper boundary of the background scattering length of the Yb(${}^3\mathrm{P}_2, m_J=0$)-Li(${}^2\mathrm{S}_{1/2}, F=1/2, m_F=+1/2$) system is estimated, revealing the absence of useful Feshbach resonances. These observations are qualitatively consistent with the theoretical calculations.Comment: 7 pages, 4 figure

Impact of binary interactions on the diffuse supernova neutrino background

Binary interactions, especially mass transfer and mergers, can strongly influence the evolution of massive stars and change their final properties and the occurrence of supernovae. Here, we investigate how binary interactions affect predictions of the diffuse flux of neutrinos. By performing stellar population syntheses including prescriptions for binary interactions, we show that the resulting detection rates of the diffuse supernova neutrino background is enhanced by 15%-20% compared to estimates without binary considerations. A source of significant uncertainty arises due to the presently sparse knowledge of the evolution of rapidly rotating carbon-oxygen cores, especially those created as a result of mergers near the white dwarf to core collapse boundary. The enhancement effect may be as small as a few percent if the effects of rotation in postmerger systems are neglected, or as large as 75% if trends are extrapolated. Our estimates serve to highlight that binary effects can be important.Comment: 12 pages, 8 figures, matches published versio

Single sheet tester having open magnetic path for measurement of magnetostriction of electrical steel sheet

A single sheet tester having closed magnetic path (a closed type of SST) has a problem that measurement accuracy of magnetostriction is considerably affected by electromagnetic force between specimen and yoke. Therefore, an open type has been developed. In order to get uniform flux distribution in a sufficiently large region, a compensating magnetizing winding is installed, and a method of waveform control is investigated, in which applied voltages to main and compensating windings are adjusted individually. The effectiveness of the newly developed open type is demonstrated by measuring magnetostrictions of thin amorphous sheet as well as highly grain-oriented silicon steel sheet</p

Measuring System of Magnetostriction Under AC Excitation Using Optical Methods

A measuring system for magnetostriction of silicon steel sheet using optical methods and a single sheet tester has been developed to establish a standard test method for IEC and JIS. Various factors affecting measurement accuracy and reproducibility of the developed system are examined. Two optical instruments, such as a laser Doppler vibrometer and a heterodyne displacement meter, are compared. 3-D characteristics of magnetostriction under ac excitation in the rolling direction are measured up to 2.0 T </p